Froth flotation of a nickel-copper sulfide matte



Pawnee-9,1847

TH ROTATION OF A menu-corona slums MATTE William Kelvin Spronle, George Alan Harcourt, and Ernest Herbert Bole, Copper Ciii. On ario. Canada, allignora to The International Nickel Oompany, Inc, New York, N. Y., a corporation ofllelavlare No Drawing. fipplioaton September 19. 1945, Serial No. 817,150. In Canada March 14, ms

1 Claims. (Cl. 241-) The present invention relates to a novel fiotation rocess for concentrating comminuted matte consisting principally of nickel sulfide, copper sulfide, and a metallic copper-nickel alloy into a copper concentrate substantially free from nickel sulfide and a nickel concentrate substantially free from copper sulfide and to a fiotation reagent therefor.

Heretoiore, many flotation reagents have been proposed for the selective notation of copper sulfide minerals irom copper ores. Although attempts have been made to discover the chemical properties which result in a substance acting as a good collecting agent, no general principles have been established which will enable a person skilled in the art to predict with certainty whether or not a reagent will have superior collecting properties for copper sulfide minerals. Similarly, one skilled in the art cannot predict whether or not a compound will give satisfactory results in the segregation of copper sulfide and nickel sulfide from a matte consisting principally of copper sulfide, nickel sulfide and a metallic copper-nickel alloy, While it has been stated that the presence of trivalent nitrogen or divalent sulfur causes a compound to be a good collector ior co per sulfide minerals, nevertheless substances such as triphenyl guanidine, mercapto-benzothiazol and the product 'of the reaction between butyl amine and n-val'eraldehyde, all of which contain trivalent nitrogen or divalent sulfur. do not in all cases afiord satisfactory separation of copper sulfide irom nickel sulfide.

It is. of course, true that many empirically discovered collecting reagents for copper sulfide minerals have been patented. For example, in U. 8. Patent No. 1,364,308, Perkins et al. propose the use of aromatic thiourea compounds such as thiocarbanilide or diphenyl thiourea for the dotation of ores, such as the Utah copper Cempany's ore consisting principally of chalcocite, chalcopyrite and gamma. These patentees state that pine oil should be added to obtain good irothing qualities. In U. 8. Patent No. 2,180,926, Jayne discloses the use of substituted biguanides, their salts and aldehyde condensation products in the selective flotation of copper sulfide minerals from ore containing chalcocite, hornite, enargite and pyrite. In U. 8. Patent No. 1,810,217, Elley discloses the flotation of Phelps-Dodge Corporation Copper Queen ore by the use of alkylsubstituted thioureas such as dibutylthiourea.

In our a fiotation reagent is desired which has so high a preference for copper sulfide that a considerably greater percentage of copper sulfide is caused to fioat than is the case with the reagents proposed by the prior art and particularly by the above-mentioned patentees. In addition. these results must be obtained with a matte or raw material comprising substantially all copper sulfide, nickel sulfide and a metallic copper-nickel alloy, that is to say, a matte substantially free from iron. Thus, the novel collecting reagents for our process give unusually good results when used with a matte or raw material consisting principally of copper sulfide, nickel sulfide and a metallic copper-nickel alloy but do not give commercially satisfactory results when used with an unsmelted ground Sudbury ore containing a considerable amount of iron and consisting of pyrrhotite, chalcopyrite, pentlandlie and gangue.

It is an object of the present invention to employ a novel flotation agent for our process which is capable of yielding greatly improved results in the separation of copper sulfide and nickel sulfide from mattes or raw materials consisting principally of copper sulfide, nickel sulfide and a metallic copper-nickel alloy, and which is capable of being utilized in a practical manner on an industrial scale with conventional flotation equipment.

The present invention also contemplates the utilization of a notation process on comminuted matte or raw material consisting principally of copper sulfide, nickel sulfide and a metallic copper-nickel alloy having as end products nickel sulfide substantially free from copper sulfide and copper sulfide substantially free from nickel sulfide.

It is within the scope of the present invention to employ a novel fiotation rea ent for our process which will fioat copper sulfide as a froth recoverable as a copper-rich concentrate and which will cause nickel sulfide to be depressed. whence it may be recovered as a nickel-rich concentrate.

It is a feature 01' the present invention that outstanding results are obtained without necessarily using an auxiliary frothing agent and within a much shorter time of flotation as compared with the flotation reagents of the prior art.

Various other objects, advantages and features of the present invention will become apparent from the following detailed description.

we have discovered that diphenyl guanidine and diortho tolyl guanidine, when used as fiotation reagents. eifect outstanding separation of nickel sulfide and copper sulfide from mattes consisting principally of nickel sulfide. copper sulfide and a metallic copper-nickel alloy.

The matte is preferably prepared for the flotation operation as described in our co-pending applications Serial No, 527,510, now U. 8. Patent No. 2,419,973, and Serial No, 527,511. Although this process can be applied to mattes containing about 8% to about 30% or more sulfur and the balance substantially all copper and nickel in any proportions, the preferred matte compositions are about 30% to 65% nickel, 20% to 24% sulfur and 50% to 15% copper. It will be understood by those skilled in the art that this preferred range of compositions applies particularly to ore which has been treated in a blast furnace or reverberatory furnace and then blown to bessemer matte. However, matte or raw material having the above-noted composition may be obtained by melting together scrap copper-nickel alloys and sulfur in the desired proportions or in any other suitabe manner.

As the matte leaves the bessemer converter it is in the molten state. If the matte is not molten, it is heated until fu ion occurs. The molten matte is slowy cooled from the temperature at which crystallization begins to a temperature of about 950 F. or lower, the cooling occurring over a period of about 1 day to about 15 days. However. more satisfac ory results are obtained if the slow cooling is continued to a temperature of about 200 F. We have found that the slow cooling is particularly important within the temperature range of about 1300 F. to about 950" F. The slowly cooled matte consists of mechanically Joined crystals of nickel sulfide, copper sulfide and copper-nickel alloy, these crystals being of sufiiclent size that they may be mechanically separated, for example, by crushing and grinding. Although we have described, in detail, a method of preparing material suitable for use with our novel flotation process. it is to be understood that we do not limit ourselves to this particular method of preparation.

According to the invention. the slowly cooled matte is crushed and ground to such a degree of fineness that the crystals of nickel sulfide, copper sulfide and copper-n ckel alloy are substantially freed from each other and are capable of being treated by flotation. We prefer to grind the matte until all the material ,wi l pass a IOO-mesh screen and about to about 50% is retained on a 325- mesh screen. Sufiicient water is added to the matte during grinding to form a pulp whose solid content is between about 10% and about 40%. A suilicient amount of a suitable alkaline reagent, for example lime, is added to maintain a pH of about 12.4. This pH value is not critical however and. broadly speaking, may vary within the ranges of about pH 10.0 to about pH 12.4 when using lime. Of course, certain other alkaline reagents such as sodium hydroxide may be utilized, but

we have found the use of lime preferable,

We also add between about 0.25 pound and 1.0 pound of our novel flota ion reagent, to wit: diphenyl guanidine or diortho tolyl guanidine. per ton of matte, at the grinding mill. The pulp is then treated by froth flotation. Sufiicient froth is commonly produced without the aid of any auxiliary frothing agents. However, if additional frothing is desired, a suitable auxiliary frothing agent, such as pine oil. may be added. The copper sulfide is floated and may be drawn of! with the froth as a copper concentrate containing only about 1% to about 10% nickel sulfide. The nickel sulfide together with the larger portion of the metallics is depressed and is withdrawn as a nickel 4 concentrate containing only about 0.5% to about 5% copper sulfide.

In commercial practice, it has been found advantageous to carry out the flotation operation in a series of three to six roughing and cleaning stages and to regrind the copper rougher concentrate, and sometimes the nickel concentrate, before cleaning. Magnetic material consisting largely of copper-nickel alloy is removed from the pulp either before flotation, or from the notation products or at both stages of the process. This magnetic material may be treated by known methods. After nickel and copper concentrates of desired purity are obtained, they are each dewatered and marketed or treated in any suitable manner to recover metallic nickel and metallic copper from the sulfides.

For a better understanding of the present invention by those skilled in the art. the following specific and illustrative examples are given:

Example N0, 1

A typical bessemer matte having the following composition was used:

Element Per ocnt 'lotal The matte, which was at a temperature of about 1600 F. and still molten from its production, was slowly cooled to a temperature of about 300 F. over a period of about 16 days. The cooled. solidified matte was crushed and then ground in a saturated aqueous solution of hydrated lime to which about 0.5 pound of diphenyl guanidine was added per ton of matte. The grinding was continued until all the material would pass through a IOU-mesh screen and about 35% was retained on a 325-mesh screen.

The finely ground matte was found to consist of discrete, mechanically freed particles of copper sulfide, nickel sulfide and a metallic coppernickel alloy which, together with the hydrated lime and dlphenyl guanidine, formed a pulp having a pH 01' about 12.4 and a pulp density of about 25% solids. After being discharged from the grinding mill, the pulp was introduced into a mechanical type flotation cell. Due to the novel collecting action of the diphenyl guanidine. the copper sulfide together with a small portion of the metallics was selectively floated and concentrated into the froth to form a rougher copper concentrate while the nickel sulfide together with the remainder of the metallics was depressed to form a rougher nickel concentrate. It was not necessary to add a further frothing agent to the pulp as sufiicient i'rothing resulted from the use of the diphenyl guanidine.

In this manner. the copper sulfide was to a large extent separated from the nickel sulfide. However, the rougher copper concentrate still contained about 14.5% nickel and, accordingly, further purification was desirable. To this end. the rougher copper concentrate was reground in the presence of about 0.4 pound of diphenyl guanidine per ton of matte together with cumcient hydrated lime to maintain a pH of about 12.4. The grinding was continued until all the material would pass through a ZOO-mesh screen and about 7% was retained on a 325-mesh 5. screen. The resulting pulp. having a density of about 15% solids, was fioated and. as previously described. separated into a froth containing cop per sulfide to ether with a small portion of the metallics and into a depressed nickel concentrate containing nickel sulfide together with the remainder of the metallics. The cleaned copper concentrate containing about 62.0% copper and about 6.5% nickel was subjected, without further grinding to a third flotation operation. the

pulp density being about 12% solids. The recleaned copper concentrate was dewatered and passed through a magnetic separator. thus being divided into a m netic portion consisting mostly of nickel-copper alloy and a final copper product consisting of substantially pure copper suliide having a low nickel content of about 4.5%.

The nickel sulfide product from the recleaning operation wa combined with the nickel products of the two previous flotation steps. The resulting nickel concentrate was passed through a magnetic separator which formed a magnetic product consisting largely of copper-nickel alloy and a non-magnetic final nickel concentrate. These results were obtained in the unusually short total floating time of 18 minutes. The final dried product obtained had the following assays and represented the following recoveries:

Assay Recovery Material Per cent Per cent Per cent Per cent Cu N Cu Ni Feed 37. 40. 4 100. 00 ma 0 Cu Concentrate 75. 0 4. 5 83. 2 4. 6 Ni (onccntrata l. 4 67. 3 1.4 61.8 Metallic: 20. 0 02. 0 l5. 4 33. 0

Example No. 2

A typical bessemer matte having the following composition was used:

Element Total Recovery Material Per cenl Per cent Per cent Ni Cu Ni Feed Cu Concentrate Ni Concentrate. Metailics.

l l m. l. 3. 70. 20. 5.

It is to be understood that the preceding examples are purely illustrative of our invention and that many changes can be made therein by one skilled in the art without departing from 6. thespiritandloopeoftheinrention. Fore!- emple, although with the particular matte compositions illustrated a metallic copper-nickel slloy appeared in the slowly cooled matte. it is apparent that no metallics will be formed if the sulfur present in the or inal charge issumcient to combine with all the copper and nickel present. In this case the magnetic separation step could be dispensed with and the final products of the flotation process would be substantially pure copper sulfide and substantially pure nickel sulfide. both of these compounds being free from metallics.

It is also within the purview of the invention to magnetically separate the metallic coppernickel alloy from the sulfide; before flotation.

Moreover. those skilled in the art will recognize that the amount of each reagent required to produce a clean concentrate by froth flotation cannot be stated precisely. It is well recognized by those skilled in the art'that. as in the case of naturally occurring ores, different samples of matte of similar composition will require slightly different amounts of the various reagents. Accordingly. those skilled in the art will recognize that the various amounts of reagents set forth herelnbefore are purely illustrative of the general magnitude of the quantities involved and that variations will occur dependent upon various local conditions.

Furthermore. while the present process has been described in conjunction with bessemer matte produced from Sudbury ore, it is to be understood that the present process can be utilined with equally satisfactory results in the separation of metallic nickel from metallic copper. In such an application of the present process. copper-nickel scrap. for example. can be melted with sufilcient sulfur to provide a product having essentially the same composition as bessemer matte and this synthetic bessemer matte can then be subjected to regulated slow cooling in the same manner as bossemer matte produced in the treatment of Budbury or other copper-nickel sulfide ores. Similarly, other materials containing copper and nickel. but devoid of or containing only small amounts of sulfur. can be sulfldized to produce a matte consisting essentially of copper, nickel and sulfur and the matte so produ ed sublected to regulated slow cooling followed by comminution and separation of the comminuted material into a product consisting essentially of copper sulfide and a product consisting essentially of nickel sulfide. In this connection. it is to be noted that in the separation of the comminuted crystallized sulfides in wcordance with the preferred embodiment of the present invention both the nickel-rich fraction and the copper-rich fraction are termed concentrates although the material of the nickel cowentrate is depressed while the material of the copper concentrate is floated and removed in the froth.

We claim:

1. A process for recovering copper sulfide and nickel sulfide from bessemer matte essentially devoid of iron which comprises slowly cooling said bessemer matte from the molten state to a temperature below about 950 F. to form a mass containing mechanically joined crystals of copper sulfide and nickel sulfide together with a coppernickel alloy. comminuting the slowly-cooled mass in the presen e of a sufilclent quantity of an alkaline reagent to maintain a pH of about 10.0 to about 12.4, adding about 0.25 to about 1.0 pound of a compound selected from the group consisting of diphenyl guanidine and diortho tolyl guanidine per ton of matte, subjecting the comminuted mass to froth flotation whereby copper sulfide is floated and recovered in the froth as a copper concentrate, the nickel sulfide being depressed as a nickel concentrate, and removing said copper-nickel alloy from said copper concentrate and said nickel concentrate by magnetic separation.

2. A process for separating nickel sulfide and copper sulfide as concentrates from a ground, slowly-cooled bessemer matte substantially free from iron and containing an appreciable quantity of a copper-nickel alloy which comprises sub- ,iecting said ground, slowly-cooled matte to froth flotation at a pH of about 10.0 to about 12.4 in the presence of about 0.25 to about 1.00 pound of a compound selected from the group consisting of diphenyl guanidine and diortho tolyl guanidine per ton of matte to form a depressed rougher nickel concentrate and a. floated rougher copper concentrate, treating said rougher copper concentrate by selective froth flotation to obtain a purified copper concentrate together with an additional quantity of nickel concentrate, and removing said copper-nickel alloy from said copper concentrate by magnetic separation.

3. A process for recovering copper sulfide and ni kel sulfide from bessemer matte which comprises slowly cooling said bessemer matte from the molten state to a temperature below about 950 F. to form a mass containing copper sulfide, nickel sulfide and a copper-nickel alloy, comminuting the slowly-cooled mass in the presence of a sufllcient quantity of an alkaline reagent to maintain a pH of about 10.0 to about 12.4 and a pulp density of about 25% solids, adding about 0.25 to about 1.0 pound of diphenyl guanidine per ton of matte, subjecting the comminuted mass to froth flotation whereby copper sulfide is floated and recovered in the froth as a copper concentrate, the nickel sulfide being depressed as a nickel concentrate, and removing at least a portion of said copper-nickel alloy by magnetic separation.

4. A process for separating ni kel sulfide and copper sulfide as concentrates from a ground, slowly-cooled bessemer matte substantially free from iron and containing an appreciable quantity of a copper-nickel alloy which comprises subjecting said ground, slowly-cooled matte to froth flotation while maintaining a pH of about 10 to about 12.4 in the presence of a compound selected from the group consisting of diphenyl guanidine and diortho tolyl guanidine to form a depressed rougher nickel concentrate and a floated rougher copper concentrate, treating said rougher copper oncentrate by selective flotation to obtain a purified copper concentrate together with an additional quantity of nickel concentrate, and removing said copper nickel alloy from said copper concentrate and said nickel concentrate by magnetic separation.

5. A process for separating and recovering nickel sulfide and copper sulfide as concentrates from a smelted mass substantially free from iron and containing mechanically joined crystals of nickel sulfide and copper sulfide which comprises comminuting said mass to a size finer than 100- mesh in a saturated aqueous solut on of hydrated lime to obtain a pH of about 12.4 and a pulp density between about 10% and about 40% solids, adding about 0.5 pound of diphenyl guanidine per ton of mass while grinding, treating the comminuted mass by froth flotation whereby the copper sulfide is floated as a copper concentrate and the nickel sulfide is depressed as a nickel concentrate, and further purifying the copper concentrate by successive froth flotation steps in the presence of diphenyl guanidine.

6. A process for separating and recovering nickel sulfide and copper sulfide as concentrates from a smelted mass essentially free from iron and containing mechanically joined crystals of nickel sulfide and copper sulfide which comprises comminuting said mass in a saturated aqueous solution of hydrated lime until about 35% thereof is retained on a 325-mesh screen, adding about 0.5 pound of diphenyl guanidine per ton of mass while grinding, treating the comminuted mass by froth flotation while maintaining a pH of about 10.0 to about 12.4 whereby the copper sulfide is floated as a copper concentrate and the nickel sulfide is depressed as a nickel concentrate, and further purifying the copper concentrate by successive froth flotation steps in the presence of about 0.5 pound of diphenyl guanidine per ton.

'l. A process for recovering copper sulflde and nickel sulfide from bessemer matte substantially free from iron which comprises slowly cooling said bessemer matte from the molten state to a temperature below about 950 F. over a period of about one to about fifteen days, comminuting the slowly-cooled matte to a size finer than about -mesh in the presence of a sufilcient quantity of an alkaline reagent to maintain a pH of about 10.0 to about 12.4, adding about 025 to about 1.0 pound of diphenyl guanidine per ton of mass, and subjecting the comminuted mass to froth flotation whereby copper sulfide is floated and recovered in the froth as a copper concentrate, the nickel sulfide being depressed as a nickel concentrate.

8. A process for separating nickel sulfide and copper sulfide as concentrates from a ground, slowly-cooled bessemer matte which comprises subjecting said ground, slowly-cooled matte to froth flotation while maintaining a pH of about 10 to about 12.4 in the presence of a compound selected from the group consisting of diphenyl guanidine and diortho tolyl guanidine to form a depressed rougher nickel concentrate and a floated rougher copper concentrate, and treating said rougher copper concentrate by selective froth flotation to obtain a purified copper concentrate together with an additional quantity of nickel concentrate.

0. A process for separating nickel sulfide and copper sulfide as concentrates from a ground, slowly-cooled bessemer matte which comprises subjecting said ground, slowly-cooled matte to froth flotation while maintaining a pH of about 10 to about 12.4 in the presence of about 0.25 to about 1.00 pound of a compound selected from the group consisting of diphenyl guanidine and diortho tolyl guanidine per ton of matte to form a depressed rougher nickel concentrate and a floated rougher copper concentrate, and treating said rougher copper concentrate by selective froth flotation to obtain a purified copper concentrate together with an additional quantity of nickel concentrate.

10. A process for separating and recovering nickel sulfide and copper sulfide as concentrates from a smelted mass substantially devo d of iron and containing mechanically joined crystals of nickel sulfide and copper sulfide which comprises comminuting said mass in a saturated aqueous solution .01 hydrated lime, adding about 0.25 to about 1.00 pound of diphenyl guan dine per ton of matte whfle grinding, subjecting the ground mass to froth flotation while maintaining a pH of about 10.0 to about 12.4 whereby the copper sulfide is floated as a copper concentrate and the nickel sulfide is depressed as a nickel concentrate, and further purifying the copper concentrate by successive froth flotation steps in the presence of diphenyl guanidine.

11. A process for recovering copper sulfide and nickel sulfide from bessemer matte which comprises slowly cooling said bessemer matte from the molten state to a temperature below about 950 F., comminuting the slowly-cooled matte in the presence of a sufiicient quantity of an alkaline reagent to maintain a pH of about 10.0 to about 12.4, adding about 0.25 to about 1.0 pound of a compound selected from the group consisting of diphenyl guanidine and diortho tolyl guanidine per ton of matte, and subjecting the comminuted mass to froth flotation whereby copper sulfide is floated and recovered in the froth as a copper concentrate, the nickel sulfide being depressed as a nickel concentrate.

12. A process for separating nickel sulfide from copper sulfide which comprises subjecting a comminuted copper-nickel matte substantially devoid of iron and containing discrete particles of nickel sulfide and copper sulfide to selective froth flotation after adding about 0.25 to about 100 pound of a compound selected from the group consisting of diphenyl guanidine and diortho tolyl guanidine per ton of matte while maintaining a pH of about 10.0 to about 12.4 whereby the copper sulfide is floated for recovery in the froth and the nickel sulfide is depressed.

13. A process for separating nickel sulfide from copper sulfide which comprises subjecting a comminuted smelted mass substantially devoid of iron and containing discrete particles of nickel sulfide and copper sulfide to selective froth flotation after adding a compound selected from the group consisting of diphenyl g'uanidine and diortho tolyl guanidine while maintaining a pH of about 10 to about 12.4 and a pulp density between about 10% and about 40% solids whereby the copper sulfide is floated for recovery in the froth and the nickel sulfide is depressed.

14. A process for separating and recovering nickel sulfide and copper sulfide as concentrates from a bessemer matte containing mechanically joined crystals of nickel sulfide and copper sulfide which comprises comminuting said matte in a saturated aqueous solution of hydrated lime, adding about 0.25 to about 1.00 pound of diphenyl guanidine per ton of matte while grinding, subjecting the comminuted matte to froth flotation whereby the copper sulfide is floated as a copper concentrate and the nickel sulfide is depressed as a nickel concentrate. further purifying the copper concentrate by successive froth flotation steps in the presence of diphenyl guanidine, and combining the nickel concentrates from said froth flotation steps.

15. A process for separating nickel sulfide from copper sulfide which comprises subjecting a comminuted smelted mass substantially devoid of iron and containing discrete particles of nickel sulfide and copper sulfide to selective froth fiotation while maintaining a pH of about 10 to about 12.4 after having added diphenyl guanidine whereby the copper sulfide is floated for recovery as a froth and the nickel sulfide is depressed.

16. A process for separating nickel sulfide from copper sulfide which comprises subjecting a comminuted bessemer matte containing discrete particles of nickel sulfide and copper sulfide to selective froth flotation while maintaining a pH of about 10 to about 12.4 after adding a compound selected from the group consisting of diphenyl guanidine and diortho tolyl guanidine whereby the copper sulfide is floated for recovery as a froth and the nickel sulfide is depressed.

WILLIAM KELVIN SPROULE. GEORGE ALAN HARCOURT. ERNEST HERBERT ROSE.

REFERENCES CITED The following references are of record in the file of this patent:

Engineering and Mining Journal, Nov. 10, 1930, pages 468-412.

Milling Methods, 1930, pages 813 to 820, and 341.

Certificate of Correction Patent No. 2,432,456.

December 9, 1947.

WILLIAM KELVIN SPROULE ET AL.

It is hereby that errors appear numbered patent requu after the word "converter under the heading "Per cent, for 23" read correction as fo 870 F.; column 6, line 34, for can read can; co

read 0.26 lines 32 and 33 same claim, line 57, claim 9, for "o 25' read with these corrections case in the Patent Oflice.

in the printed specification of the above llows: Column 3, line 20, insert a comma 1, right hand column, 5, line 53, for 370 F. read line 31, claim 7, for "0 25 each occurrence, read matte;

Signed and sealed this 13th day of April, A. D. 1948.

THOMAS F. MURPHY,

Assistant 00m mias ma r of Patents.

mass to froth flotation while maintaining a pH of about 10.0 to about 12.4 whereby the copper sulfide is floated as a copper concentrate and the nickel sulfide is depressed as a nickel concentrate, and further purifying the copper concentrate by successive froth flotation steps in the presence of diphenyl guanidine.

11. A process for recovering copper sulfide and nickel sulfide from bessemer matte which comprises slowly cooling said bessemer matte from the molten state to a temperature below about 950 F., comminuting the slowly-cooled matte in the presence of a sufiicient quantity of an alkaline reagent to maintain a pH of about 10.0 to about 12.4, adding about 0.25 to about 1.0 pound of a compound selected from the group consisting of diphenyl guanidine and diortho tolyl guanidine per ton of matte, and subjecting the comminuted mass to froth flotation whereby copper sulfide is floated and recovered in the froth as a copper concentrate, the nickel sulfide being depressed as a nickel concentrate.

12. A process for separating nickel sulfide from copper sulfide which comprises subjecting a comminuted copper-nickel matte substantially devoid of iron and containing discrete particles of nickel sulfide and copper sulfide to selective froth flotation after adding about 0.25 to about 100 pound of a compound selected from the group consisting of diphenyl guanidine and diortho tolyl guanidine per ton of matte while maintaining a pH of about 10.0 to about 12.4 whereby the copper sulfide is floated for recovery in the froth and the nickel sulfide is depressed.

13. A process for separating nickel sulfide from copper sulfide which comprises subjecting a comminuted smelted mass substantially devoid of iron and containing discrete particles of nickel sulfide and copper sulfide to selective froth flotation after adding a compound selected from the group consisting of diphenyl g'uanidine and diortho tolyl guanidine while maintaining a pH of about 10 to about 12.4 and a pulp density between about 10% and about 40% solids whereby the copper sulfide is floated for recovery in the froth and the nickel sulfide is depressed.

14. A process for separating and recovering nickel sulfide and copper sulfide as concentrates from a bessemer matte containing mechanically joined crystals of nickel sulfide and copper sulfide which comprises comminuting said matte in a saturated aqueous solution of hydrated lime, adding about 0.25 to about 1.00 pound of diphenyl guanidine per ton of matte while grinding, subjecting the comminuted matte to froth flotation whereby the copper sulfide is floated as a copper concentrate and the nickel sulfide is depressed as a nickel concentrate. further purifying the copper concentrate by successive froth flotation steps in the presence of diphenyl guanidine, and combining the nickel concentrates from said froth flotation steps.

15. A process for separating nickel sulfide from copper sulfide which comprises subjecting a comminuted smelted mass substantially devoid of iron and containing discrete particles of nickel sulfide and copper sulfide to selective froth fiotation while maintaining a pH of about 10 to about 12.4 after having added diphenyl guanidine whereby the copper sulfide is floated for recovery as a froth and the nickel sulfide is depressed.

16. A process for separating nickel sulfide from copper sulfide which comprises subjecting a comminuted bessemer matte containing discrete particles of nickel sulfide and copper sulfide to selective froth flotation while maintaining a pH of about 10 to about 12.4 after adding a compound selected from the group consisting of diphenyl guanidine and diortho tolyl guanidine whereby the copper sulfide is floated for recovery as a froth and the nickel sulfide is depressed.

WILLIAM KELVIN SPROULE. GEORGE ALAN HARCOURT. ERNEST HERBERT ROSE.

REFERENCES CITED The following references are of record in the file of this patent:

Engineering and Mining Journal, Nov. 10, 1930, pages 468-412.

Milling Methods, 1930, pages 813 to 820, and 341.

Certificate of Correction Patent No. 2,432,456.

December 9, 1947.

WILLIAM KELVIN SPROULE ET AL.

It is hereby that errors appear numbered patent requu after the word "converter under the heading "Per cent, for 23" read correction as fo 870 F.; column 6, line 34, for can read can; co

read 0.26 lines 32 and 33 same claim, line 57, claim 9, for "o 25' read with these corrections case in the Patent Oflice.

in the printed specification of the above llows: Column 3, line 20, insert a comma 1, right hand column, 5, line 53, for 370 F. read line 31, claim 7, for "0 25 each occurrence, read matte;

Signed and sealed this 13th day of April, A. D. 1948.

THOMAS F. MURPHY,

Assistant 00m mias ma r of Patents. 

